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Providing perspectives on recent research into vitamins and nutritionals


Vitamin D and Avoiding Hospitals

By Michael McBurney

Despite the fact that skin can make vitamin D when exposed to sunlight, the use of sunscreen and the amount of time spent indoors limits vitamin D synthesis. Thus, almost 1/3 of Americans are vitamin D deficient (defined as serum 25-hydroxyvitamin D levels <50 nmol/L). The prevalence of vitamin D deficiency is higher in those with darker skin. Why? Because skin pigmentation increases the amount of sun exposure required to synthesize vitamin D. What are the consequences of vitamin D deficiency?

Extreme deficiency, 25(OH)D concentrations <20 nmol/L, leads to rickets. Vitamin D is required for calcium absorption and deposition to create bones and teeth. Without vitamin D, calcification does not occur, children develop soft bones and misshapen limbs. Because bones are metabolically active tissues, there is constant rebuilding. Adults who are vitamin D deficient do not rebuild bone properly and their bones become brittle (osteoporitic) and easily broken. Are there effects of vitamin D deficiency other than bone health?

Smith and colleagues hypothesized that low vitamin D status might increase risk of anemia, especially anemia with inflammation. They conducted a cross-sectional analysis of 638 healthy individuals living in Georgia. Serum 25(OH)D concentrations were significantly associated with total circulating iron concentrations. Among black individuals, the chances of anemia were 6X higher for those with vitamin D levels <50 nmol/L compared to those ≥50 nmol/L.

In a retrospective cohort analysis of 4,508 adult inpatients at 2 Boston teaching hospitals, Quraishi and colleagues report low vitamin D status is associated with an increased risk of hospital-acquired new-onset delirium (HANOD) even after adjusting for age, sex, race (non-white vs white), patient type (medical vs surgical), and Deyo-Charlson index (a measure of the burden of chronic illness in the study group). The mean serum 25(OH)D concentration was 55 nmol/L.

They write: “Results suggest that pre-hospital vitamin D status may be a modifiable risk factor for HANOD. We hypothesize that serum 25(OH)D levels are associated with optimal expression of endogenous proteins involved with the maintenance of neuronal health in the areas of the central nervous system responsible for cognition.”

Having watched the movie “Still Alice”, striving to meet dietary recommendations to support brain function by maintaining optimal nutritional levels of vitamins (and the long-chain omega-3 fatty acid, DHA) just makes sense.

Low vitamin D status, serum 25(OH)D concentrations < 50 nmol/L, is never a good thing. Low vitamin D status is associated with increased risk of infection after surgery, a greater risk of prostate cancer, a greater risk of falls and fractures in the elderly, and increased risk of diabetes, hypertension and coronary heart disease.

Why risk your future health? Spend some time in the sunshine. Choose vitamin D rich foods. Use a vitamin D supplement to help meet your DRI. Our goal is to maintain serum 25 (OH)D concentrations ≥ 50 nmol/L.

Main Citations

Smith EM, Alvarez JA, Martin GS, Zughaier SM, Ziegler TR, Tangpricha V. Vitamin D deficiency is associated with anaemia among African Americans in a US cohort. 2015 Br J Nutr doi:10.1017/S0007114515000999

Quraishi SA, Litonjua AA, Elias KM, Gibbons FK, Giovannucci E, Camargo Jr CA, Christopher KB. Association between pre-hospital vitamin D status and hospital-acquired new-onset delirium. 2015 Br J Nutr doi: 10.1017/S0007114515001245